Thread-cutting mechanism for sewing-machines



I 2 Sheets-Sheet 1.

(No Model.)

A. H. KINDER. THREAD GUTTING' MEGHANISM FOR SEWING MACHINES. No. 588,153. Patented Aug..17, 1897.

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(No Model.) 2 Sheets-Sheet 2.

A. H. KINDER. THREAD CUTTING MEGHANISM FOR SEWING MACHINES. No. 588,158.. Patented A '17-, 1897.

UNITED STATES PATENT OFFICE.

ARTHUR H. KINDER, OF BOSTON, MASSACHUSETTS.

THREAD-CUTTING MECHANISM FOR SEWlNG-MACHINES.

SPECIFICATION formingpart of Letters Patent No. 588,153, dated August 17, 1897.

Application filed September 20, 1895. Serial No- 563,060. (No model.)

Be it known that I, ARTHURH. KINDER, of Boston, county of Suifolk, State of Massachusetts, have invented an Improvement in Thread-Cutting Mechanism for Sewing-Machines, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

In many classes of work it is very desirable to cut or sever the thread as close as possible to the work whether using an upper or under thread, or both, in order to leave but little trimming to be afterward effected, and it is very important that the operator can sever the thread without having the attention taken from the stitching. Particularly is this latter result desirable when the work has heavy embroidery applied thereto or when ornament-al stitching is being done.

This invention has for its object the production of thread-cutting mechanism for sewing-machines whereby the upper or under thread, or both, can be severed close to the work and under full control of the operator, means being also provided for drawing oif the thread prior to cutting it, so that a sufficient end will be left when sewing is begun again.

Figure 1, in side elevation, represents a sufficient portion of a sewing-machine to be understood with one form of my invention applied thereto. Fig. 2 is a left-hand end view of the machine shown, in Fig. 1. Fig. 3 is an enlarged front view of the upper-threadcutting mechanism shown in Figs. 1 and 2. Fig. 4: is a sectional view thereof, taken on the irregular line x 00, Fig. 3. Fig. 5 is a plan view of the under-thread cutter detached, which is shown in Figs. 1 and 2. Fig. 6 is a vertical section thereof on the line y y, Fig. 5, showing the manner of severing the thread. Fig. 7 is a front elevation of a modified form of upper-thread-cutting mechanism; Fig. 8, a section thereof taken on the line y 3 Fig. 7.

Referring to the drawings Figs. .1 and 2,

the bed-plate A, overhanging arm A, needleactuating shaft A the head A needle-bar N, carrying an eye-pointed needle n, presserbar P, shuttle S for the under thread, and its raceway S may be and are all of usual and well-known construction and operation, the shuttle-actuating devices being omitted to more clearly show the parts of my invention.

To the presser-bar P, I have secured a laterally-extended stand a (see Figs. 1, 2, and 3) below the head A and having an opening-in it for a slide-bar a, extended through the stand and also through a bracket or bearing a Figs. 1 and 2, secured to the side of the arm A adjacent the head. A spiral spring 5, surrounding the bar a between the bracket a and a collar a fast on said bar, normally tends to depress -it from its elevated position (shown in Figs. 1 and 2) when notin use. The collar a has a stud on which is pivoted a link a connected to the outer arm of a lever a fulcrumed in the overhanging arm at'a". (See dotted lines, Fig. 1.)

Depending from the bed-plate are suitable bearings 19 for a rock-shaft I), having fast thereto a toe b adapted tocooperate with a lever b pivoted below the bed-plate at Z2 and connected at its rear end by a link 19 with the rear or inner arm of the lever 0. so that when the parts are in the position shown in Figs. 1 and 2 the outer end of the lever a will be elevated, raising the slide-bar a against the action of its spring .9.

The slide-bar has a longitudinal spline or rib a thereon moving in a suitable seat or recess in the stand to prevent rotation of the bar, and the latter has rigidly secured to its end below said stand a collar a provided with a pin or stud a to enter a cam-slot c in a cam a, rotatable on a depending post 0 fixed to the stand a and held in place by an annular head 0 As best shown in Figs. 3 and at, the presserfoot P is provided with a tubular shank p to embrace the presser-bar below the, stand a and held in place by a suitable screw b the presser-foot forming at its junction withthe shank a shoulder 19, on which rests the cutter-carrier, shown as a hub 61, having secured thereto a cutting-blade 61', adapted to move back and forth across the needle-hole p of the presser-foot, the hub being provided with a lug or projection d to enter a slot 0 in the cam a.

An arm 0 having a hooked end 0 extends laterally from the cam 0 (see Figs. 1 and 4) and is movable therewith into dotted-line position, Fig. 4, when the cam is turned in the direction of the arrow 15, the cam also turning thecutter-carrier d in the opposite direction, bringing the cutter cl into the dottedline position, Fig. 4.. At such time the cutter is at one side of the needle-hole p and the hooked end of the arm a at the opposite side and below the point of the needle when the latter is raised. It will be obvious that depression of the slide-bar a will, by the slotand-pin connection are, turn the cam c in the direction of the arrow into dotted-line position shown in Fig. 4, which is'the normal position of the parts during the stitching of the material.

Then the operator desires to cut the thread, he moves a knee-lever b fast on the rockshaft 1), into the position shown in Fig. 1 to lift the slide-bar a by the means described, and the movement of the stud 6L9 from the bottom to the top of the cam-groove c turnsthe cam oppositely to the arrow 15, first moving the arm 0 so that its hooked end will engage the thread between the needle and the ficient to allow partialrotation of the cam and the arm 0 before the cutter d willbe moved operative position.

across the presser-foot P into full-line position, Figs. 3 and 4, severingthe thread-at the presser-foot. lhe arm 0 acts as a'pull-ofE-to draw through the needle eye a sufficient length of thread to begin the stitching. A spring 8, surrounding the tubular shank 19, between the stand a and the cutter-carrier cl, maintains the latter seated upon the shoulder 13 of the presser-foot. The thread i is then severed close to the upper side of the work \V, Figs. 2 and 3, it being understood that as-soon as the knee-lever b is released by the operator the parts will return to their normal in- (Shown in dotted lines, Fig. 4.)

By providing the pull-off, as described, I obviate any tendency of-the short end of the thread pulling out of the needle-eye after the cutter d has severed the thread.

To limit the amount of rotation of the rockshaft 1), I have secured to the machine a bracket-arm aim the path of a set-screw e, extended througha lug Won the knee-lever, and by adjusting the set-screw e the throw of the lever can be regulated with great nicety.

In order to sever the under thread on a twothread machine, such substantially as shown in Figs. 1 and 2, I have pivotally mounted on the shuttle-race S at a cutter-carrier it somewhat like a bell-crank lever in shape, bent or curved at k around the shuttle and bifurcatedto form a knife or cutter 70 and a guide 70 adapted to slide under and press yieldinglyagainst the underside of afixed cutter-blade k at one side of the needle-path below the work-support, the knife-blade k and the guide k normally being at the opposite side of the said path. The carrier 70 is slotted at 7t to receive therein a guide-screw k screwed into the shuttle-race, and the said I plate is pivotally connected by a short link on to a lever m, the outer end of which is depressed by a spring 8 while its inner end is held between an arm m and a spring 8, at-

tached to the said arm, the latter being held movement of the said cutter across the neodle-path is so timed as to take place as the upper thread is severed, and the guide 70 directs the thread under the fixed cutter kfl the movable blade k 'passing under the 'edgeof theblade it to sever the'thread; as shown-in Fig. 6, adjacent the'under sideof the material. After the thread hasbeen cut between the'edges of the bladek and theblade k the cutting mechanism resumes its normal position, the blade k and guide it moving back from the stationary blade 10 so that-{the op erator can manipulate the under threadwh en beginning to stitch.

In Figs. 7 and S I have showna' m-odified form of upper-thread-cutting' mechanism with means to draw'oif a greater portion-of thread prior to severing it. The stand or bracket 0, which is secured to the presser-bar P, has an ofiset bearing ofor a short shaft 0 to the upper end of which issecu'red acollar 0 having a laterally-extended hooked arm 0 while beneath the stand a pinion 0 on the shaft meshes'with a segment gearor pinion 0 fast on the cam c, which latter, with the post 0 the hooked arm 0 theslide-bar 0., and the connections between the slide-bar and cam and between the cam and Buttercarrier cl are substantially the same as are shown in Figs. 1, 2, 3, and 4. Vhen the cam c is turned in the direction ofthe arrow'90, Fig. 8, thearm o isswung in the opposite direction," so thatwhen the cutting-bladed has severed the thread the armsc and=o*will be in the extended position shown in Fig. 8. As shown in Fig. 7, the-arm is adaptedi to swing in-a plane above the presser-footP, but below the needle or when the latter q's lifted, so:as to draw 0% the thread to one side, while the arm 0 is adapted to engage the thread above athread-guide n on theneedle-bar N and to swing away in the opposite direction,=so that by the combined flfect of the hWO'fLI'lDS a much larger length of thread is pulled-off before it is severed.

When the slide-bar a is'depressechthe arms c 0 are returned to normal inoperativep'osition on opposite sides of the thread ready to engage and draw it ofi at the next operation of the severing mechanism.

An inspection of either Figs. 3 or Twill is parallel to the path of the presser-bar, so

show that the lower end of the-cam-groovec' means to actuate the Pill;

that the reciprocations of the latter during the stitchingwili not cause the cam to be rotated on its foot 1. In athreadcutting mechanism .for sewing-rnachines, a Work-support, an eye-pointed needle to penetrate the material, a presserfoot, a cutting-blade pivoted to move about the shank of said foot, and at substantially right angles to and across the path of the thread, said foot having a rest to sustain the thread when severed, a pull-oft to engage the needle-thread hetween the point of the needle and the cutting-blade to aw off a sufiicient portion from the source ipniy before the said blade is moved to an.

-off and cuttingblade, substantially as described.

2. The combination with stitchforming mechanism comprising an eye-pointed needle and shuttle, a work-support, and a presser barand foot, of a laterally-movable cntting blade mounted to swing parallel to the worksupport across the presser-foot and in con-.

tact therewith to sever the needle-thread held against said foot, a fixed guide beneath the ter back and forth, a'slide-bar longitudinally movable in the stand, a stud thereon to enter the grooveof the cam and partially rotate the latter, and means controlled by the operator to move the slide-bar, substantially as described.

4. In a cutting mechanism for sewing-machines, a resser-bar and its attached presserfoot, a cutting-blade mounted on said bar to swing across the presser-foot and sever the thread, a standsecured to the resser-bar, a cam on said stand, connections between said cam and the cutting-blade, to swing the latter back and forth, a hooked arm or pull-oft adapted to be swung across the path of the thread, to draw the same through the needleeye prior to its being severed, and means to partially rotate the cam, to operate the said pull-off and thereafter move the cutting-blade to sever the thread,snbstantially as described.

In testimony whereof I have signed my name to this specification in the two subscribing witnesses.

ARTHUR H. KINDER.

presence of W'itnesses:

JOHN G. EDWARDS, AUGUSTA E. DEAN. 

